HPA
HPA全称Horizontal Pod Autoscaling ，可以实现pod的水平自动化扩缩容，比如当POD中业务负载上升的时候，可以创建新的POD来保证业务系统稳定运行，当POD中业务负载下降的时候，可以销毁POD来提高资源利用率。
HPA目前支持四种类型的指标，分别是Resource、Object、External、Pods。其中在稳定版本autoscaling/v1中只支持对CPU指标的动态伸缩，在测试版本autoscaling/v2beta2中支持memory和自定义指标的动态伸缩，并以annotation的方式工作在autoscaling/v1版本中。
refer: https://zhuanlan.zhihu.com/p/...
metrics-server
k8s api-server的支持
- --proxy-client-cert-file=/etc/kubernetes/pki/front-proxy-client.crt - --proxy-client-key-file=/etc/kubernetes/pki/front-proxy-client.key - --requestheader-allowed-names=front-proxy-client - --requestheader-client-ca-file=/etc/kubernetes/pki/front-proxy-ca.crt - --requestheader-extra-headers-prefix=X-Remote-Extra- - --requestheader-group-headers=X-Remote-Group - --requestheader-username-headers=X-Remote-Usernotes:如果你未在 master 节点上运行 kube-proxy，则必须确保 kube-apiserver 启动参数中包含--enable-aggregator-routing=true
部署
metrics-server.yaml 参见下文，部署时注意nodeSelector是否匹配
nodeSelector: kubernetes.io/os: linux kubernetes.io/arch: "amd64"kubectl create -f metrics-server.yaml
metrics api
手动获取指标
kubectl get --raw /apis/metrics.k8s.io/v1beta1/pods
or
[root@master01 hpa]# curl -H "Authorization: Bearer $toke" -k https://172.31.133.26:6443/apis/|grep metrics -C 5 { "name": "metrics.k8s.io", "versions": [ { "groupVersion": "metrics.k8s.io/v1beta1", "version": "v1beta1" } ], "preferredVersion": { "groupVersion": "metrics.k8s.io/v1beta1", "version": "v1beta1" } } ]}[root@master01 hpa]# curl -H "Authorization: Bearer $toke" -k https://172.31.133.26:6443/apis/metrics.k8s.io/v1beta1/pods |grep php -C 7 { "metadata": { "name": "php-apache-7bf64757b9-sh4rl", "namespace": "default", "selfLink": "/apis/metrics.k8s.io/v1beta1/namespaces/default/pods/php-apache-7bf64757b9-sh4rl", }, "containers": [ { "name": "php-apache", "usage": { "cpu": "31395n", "memory": "11988Ki" } } ] },CPU HPA
创建应用
kubectl run php-apache --image=k8s.gcr.io/hpa-example --requests=cpu=200m --expose --port=80
创建hpa
kubectl autoscale deployment php-apache --cpu-percent=50 --min=1 --max=10
压测
kubectl run -i --tty load-generator --image=busybox /bin/shHit enter for command promptwhile true; do wget -q -O- http://php-apache; done自动弹性
[root@master01 msxu]# kubectl get hpa -wNAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGEphp-apache Deployment/php-apache 0%/50% 1 10 1 52mphp-apache Deployment/php-apache 493%/50% 1 10 1 52mphp-apache Deployment/php-apache 493%/50% 1 10 4 52mphp-apache Deployment/php-apache 493%/50% 1 10 8 52mphp-apache Deployment/php-apache 493%/50% 1 10 10 53mphp-apache Deployment/php-apache 54%/50% 1 10 10 53mphp-apache Deployment/php-apache 49%/50% 1 10 10 54mphp-apache Deployment/php-apache 44%/50% 1 10 10 56mphp-apache Deployment/php-apache 0%/50% 1 10 10 57mphp-apache Deployment/php-apache 0%/50% 1 10 10 61mphp-apache Deployment/php-apache 0%/50% 1 10 9 61mphp-apache Deployment/php-apache 0%/50% 1 10 9 62mphp-apache Deployment/php-apache 0%/50% 1 10 1 62mMEM HPA
创建HPA
apiVersion: autoscaling/v2beta1kind: HorizontalPodAutoscalermetadata: name: php-apache-hpa namespace: defaultspec: scaleTargetRef: apiVersion: apps/v1beta1 kind: Deployment name: php-apache minReplicas: 1 maxReplicas: 3 metrics: - type: Resource resource: name: memory targetAverageUtilization: 30查看
[root@master01 hpa]# kubectl get hpaNAME REFERENCE TARGETS MINPODS MAXPODS REPLICAS AGEphp-apache Deployment/php-apache 0%/50% 1 10 1 5d17hphp-apache-hpa Deployment/php-apache 11%/30% 1 3 1 5d17h[root@master01 hpa]# kubectl describe hpa php-apache-hpa Name: php-apache-hpaNamespace: defaultLabels: <none>Annotations: <none>CreationTimestamp: Thu, 30 Apr 2020 17:57:40 +0800Reference: Deployment/php-apacheMetrics: ( current / target ) resource memory on pods (as a percentage of request): 11% (11546624) / 30%Min replicas: 1Max replicas: 3Deployment pods: 1 current / 1 desiredConditions: Type Status Reason Message ---- ------ ------ ------- AbleToScale True ReadyForNewScale recommended size matches current size ScalingActive True ValidMetricFound the HPA was able to successfully calculate a replica count from memory resource utilization (percentage of request) ScalingLimited False DesiredWithinRange the desired count is within the acceptable rangeEvents: <none>yaml
metrics-server.yaml 0.3.6
apiVersion: rbac.authorization.k8s.io/v1kind: ClusterRolemetadata: name: system:aggregated-metrics-reader labels: rbac.authorization.k8s.io/aggregate-to-view: "true" rbac.authorization.k8s.io/aggregate-to-edit: "true" rbac.authorization.k8s.io/aggregate-to-admin: "true"rules:- apiGroups: ["metrics.k8s.io"] resources: ["pods", "nodes"] verbs: ["get", "list", "watch"]---apiVersion: rbac.authorization.k8s.io/v1kind: ClusterRoleBindingmetadata: name: metrics-server:system:auth-delegatorroleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: system:auth-delegatorsubjects:- kind: ServiceAccount name: metrics-server namespace: kube-system---apiVersion: rbac.authorization.k8s.io/v1kind: RoleBindingmetadata: name: metrics-server-auth-reader namespace: kube-systemroleRef: apiGroup: rbac.authorization.k8s.io kind: Role name: extension-apiserver-authentication-readersubjects:- kind: ServiceAccount name: metrics-server namespace: kube-system---apiVersion: apiregistration.k8s.io/v1beta1kind: APIServicemetadata: name: v1beta1.metrics.k8s.iospec: service: name: metrics-server namespace: kube-system group: metrics.k8s.io version: v1beta1 insecureSkipTLSVerify: true groupPriorityMinimum: 100 versionPriority: 100---apiVersion: v1kind: ServiceAccountmetadata: name: metrics-server namespace: kube-system---apiVersion: apps/v1kind: Deploymentmetadata: name: metrics-server namespace: kube-system labels: k8s-app: metrics-serverspec: selector: matchLabels: k8s-app: metrics-server template: metadata: name: metrics-server labels: k8s-app: metrics-server spec: serviceAccountName: metrics-server volumes: # mount in tmp so we can safely use from-scratch images and/or read-only containers - name: tmp-dir emptyDir: {} containers: - name: metrics-server image: k8s.gcr.io/metrics-server-amd64:v0.3.1 imagePullPolicy: IfNotPresent args: - --cert-dir=/tmp - --secure-port=4443 - --kubelet-preferred-address-types=InternalIP - --kubelet-insecure-tls ports: - name: main-port containerPort: 4443 protocol: TCP securityContext: readOnlyRootFilesystem: true runAsNonRoot: true runAsUser: 1000 volumeMounts: - name: tmp-dir mountPath: /tmp nodeSelector: kubernetes.io/os: linux kubernetes.io/arch: "amd64"---apiVersion: v1kind: Servicemetadata: name: metrics-server namespace: kube-system labels: kubernetes.io/name: "Metrics-server" kubernetes.io/cluster-service: "true"spec: selector: k8s-app: metrics-server ports: - port: 443 protocol: TCP targetPort: main-port---apiVersion: rbac.authorization.k8s.io/v1kind: ClusterRolemetadata: name: system:metrics-serverrules:- apiGroups: - "" resources: - pods - nodes - nodes/stats - namespaces - configmaps verbs: - get - list - watch---apiVersion: rbac.authorization.k8s.io/v1kind: ClusterRoleBindingmetadata: name: system:metrics-serverroleRef: apiGroup: rbac.authorization.k8s.io kind: ClusterRole name: system:metrics-serversubjects:- kind: ServiceAccount name: metrics-server namespace: kube-system